The housing stock in the UK has changed significantly since 1921. Many homes have been constructed since then, leading to the very wide diversity that we see today. This report looks back over the past 90 years, presenting statistics that illustrate key changes and the progress that has been made in improving the nation's homes. The focus is on changes to the housing stock that have had an effect on standards of living, energy use and carbon dioxide (CO2) emissions. Impacts on health are also discussed. The report closes by considering what the housing stock will need to look like in 2050 in order to meet the UK government's target to cut CO2 emissions by 80% on 1990 levels, and the scale of the challenge that this presents. What has been achieved in the past is very substantial, but also provides an important reality check on the feasibility of achieving such large-scale changes over the next 40 years.